A slimmed-down Rob Kelley is likely to remain Washington's top running back even though Adrian Peterson is joining the Redskins.

Amid four injuries in their backfield, the Redskins signed the 33-year-old four-time All-Pro running back on Monday. But Kelley, the former "Fat Rob" who lost weight and added speed to his repertoire, should still be considered the front-runner to start Week 1 at the Arizona Cardinals.

Washington lost second-round pick Derrius Guice to a season-ending torn ACL, won't have Samaje Perine and Byron Marshall for an extended period of time because of lower-leg injuries and waived undrafted free agent Martez Carter with an injury designation. That necessitated signing Peterson -a former standout at Oklahoma who played the majority of his career with the Vikings - and fellow running back De'Veon Smith, though coach Jay Gruden gave Kelley a vote of confidence on Sunday.

"We're not looking for a starter right now," Gruden said. "We've got Rob in-house, obviously Chris Thompson, Kapri Bibbs has done a good job, Samaje I don't think is going to be very long at all. So we've got four backs right there."

On the first day of camp, Gruden was only sure of one thing: that third-down back Chris Thompson would be on the roster and figure prominently in his return from a broken fibula. Kelley, a 2016 undrafted free agent who emerged as Washington's No. 1 running back during his rookie year and started 2017 on top of the depth chart, cut his hair short, added more muscle and looks quicker to Gruden at a svelte 222 pounds.

"It was time for a change," Kelley said of trimming his dreadlocks. "It was like a bold statement showing that I'm ready to change, rather than just coming in and talking about it how much I'm going to change and stuff like that. Just change within and the hair was just like a statement."

Kelley got the first chance with the first-team offense in the Redskins' second preseason game and is trying to focus on showing his best and not the competition for the starting role.

"Early on I thought about it a lot, but now I try not to think about it," Kelley said. "I don't try and put too much on myself that potentially distracts me from actually getting better."

When Guice looked like the starter, Kelley fielded questions about taking snaps at fullback and helping out on special teams. He was willing to do whatever it took to make the team, though the 25-year-old Tulane product didn't rule out winning back the starting job he lost last season because of injuries.

"There's competition whether you think it or not," Kelley said. "I just make sure I go out there and I make a few plays that the catch the coaches' eyes and stuff like that and put myself in a great position."

He's in a great position now by default, though Gruden also said Kelley has had a great training camp. Kelley ran for just 17 yards on seven carries last week against the Jets and the bevvy of injuries created a need to bring in another running back.

"If something else happens, we're going to be really, really, really thin, so we just want to make sure we're covering all our bases right now," Gruden said.

Kelley will have to keep competing to fend off Peterson for a bulk of the carries, but that's a big step up from being on the roster bubble a month ago. More competition is for the best for Kelley, who is no stranger to overcoming odds and winning a competition as an underdog.

"I think the hurdles just make me a better player," Kelley said. "It's the team's job to keep on getting competition, to keep pushing the envelope, so it doesn't make a difference (and I've) still got to work as hard as I can."

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